Lewis Hamilton of Mercedes dominated the opening day at the Formula One Las Vegas Grand Prix, topping both of the first two practice sessions.

The seven-time world champion clocked 1 minute 33.825 seconds around the street circuit to top Thursday's second practice.

Title contender Lando Norris of McLaren was just 0.011s behind, while George Russell in the second Mercedes completed the top three.

In the earlier session, Hamilton led a Mercedes one-two ahead of team-mate Russell.

It was a boost of confidence for Hamilton, who admitted earlier this week that he wanted to walk away from Mercedes in the aftermath of the Brazilian GP, where he endured one of the worst performances of his glittering F1 career - crossing the line in 10th - a fortnight ago.

Hamilton won six of his seven titles with Mercedes, but will leave the German team at the end of the season to join Ferrari.

The Italian team was fourth and fifth with Carlos Sainz and Charles Leclerc respectively, while three-time defending champion Max Verstappen of Red Bull could manage only 17th.

Verstappen was among the drivers who complained of lack of grip in the cold track conditions in Vegas.

The Dutchman will claim his fourth consecutive world title if he outscores Norris on Saturday.

Norris, meanwhile, must take at least three points out of Verstappen's 62-point championship lead to extend the title battle to the penultimate race in Qatar next week.